1 files changed, 11 insertions, 0 deletions
diff --git a/src/strings/strings_test.go b/src/strings/strings_test.go
index 5143ec86c9..f93cf6842f 100644
--- a/src/strings/strings_test.go
+++ b/src/strings/strings_test.go
@@ -1535,6 +1535,17 @@ func TestContainsRune(t *testing.T) {
 	}
 }
 
+func TestContainsFunc(t *testing.T) {
+	for _, ct := range ContainsRuneTests {
+		if ContainsFunc(ct.str, func(r rune) bool {
+			return ct.r == r
+		}) != ct.expected {
+			t.Errorf("ContainsFunc(%q, func(%q)) = %v, want %v",
+				ct.str, ct.r, !ct.expected, ct.expected)
+		}
+	}
+}
+
 var EqualFoldTests = []struct {
 	s, t string
 	out  bool